There has been a growing need for X-ray imaging in bi-plane configuration, particularly for cardiac, vascular and interventional procedures, using two X-ray apparatuses so that an object being examined can be observed in two planes. Each of these two apparatuses comprises an arcuated structure carrying an X-ray tube and an X-ray image receptor which arcuated structure is orbitally displaceable. One of the arcuated structures is supported on a floor base and the other is suspended form a ceiling to effectively utilize space and allow these two arcuated structure to be brought into a close proximity so that their radiation isocenters coincide with the object being imaged.
In the prior art a vertical position of the radiation axis in the ceiling suspended arcuated structure was not adjustable, therefore, a table elevation had to be adjusted to a level of object being examined and could not be adjusted to a level convenient for a medical staff.
Prior art also showed a ceiling mounted arcuated structure having an X-ray tube and an image receptor slideably mounted on extremity thereof for some limited adjustments. A disadvantage of this construction was that vhen the X-ray tube and the image receptor are moved, the isocenter of the arc no longer coincides with the radiation isocenter and for this reason the object being imaged does not remain in the center of the image, but moves away so that the patient has to be repositioned.
On the other hand, in the prior art having both X-ray units mounted on the floor and being vertically adjustable, these units could not be used individually for imaging in a single plane due to physical constrains. Also, said arrangement was more congested and provided only a limited access to a patient. And further, said arrangement did not allow for a complete imaging coverage of a patient, because the units had to be in close proximity of one another.